• Welcome to The Truck Stop! We see you haven't REGISTERED yet.

    Your truck knowledge is missing!
    • Registration is FREE , all we need is your birthday and email. (We don't share ANY data with ANYONE)
    • We have tons of knowledge here for your diesel truck!
    • Post your own topics and reply to existing threads to help others out!
    • NO ADS! The site is fully functional and ad free!
    CLICK HERE TO REGISTER!

    Problems registering? Click here to contact us!

    Already registered, but need a PASSWORD RESET? CLICK HERE TO RESET YOUR PASSWORD!

External oil cooler vs internal rad one....

Something to consider--you have the dual thermo crossover. This means you don't have the bypass block off that the single thermo has. The theory I've heard, and makes sense to me, is that when the motor is up to temp the open bypass of the dual thermo lets too much coolant circulate back through the block without going through the rad, hampering the cooling process.

Heath recommends a restrictor barb fitting on the water pump for the bypass circuit. This restrictor goes in place of the stock barb fitting and has only about a 1/4 to 3/8ths" opening in it. This allows some coolant to circulate when the motor is cold and thermo is closed, but greatly slows down the circulation through the bypass. I did get Heaths' restictor, but after seeing it you could easily make your own since you are very handy.

Don
 
handcannon said:
Something to consider--you have the dual thermo crossover. This means you don't have the bypass block off that the single thermo has. The theory I've heard, and makes sense to me, is that when the motor is up to temp the open bypass of the dual thermo lets too much coolant circulate back through the block without going through the rad, hampering the cooling process.

Heath recommends a restrictor barb fitting on the water pump for the bypass circuit. This restrictor goes in place of the stock barb fitting and has only about a 1/4 to 3/8ths" opening in it. This allows some coolant to circulate when the motor is cold and thermo is closed, but greatly slows down the circulation through the bypass. I did get Heaths' restictor, but after seeing it you could easily make your own since you are very handy.

Don
Click to expand...

Supposedly GM makes it but I don't know the part # but do you have a pic of yours ?
 
Yeah I couldnt get the dealer parts guy to find anything other than the original, unless it did maintain the same part number, doubtful. However, the oddest thing, when I went in looking for a water pump previously, the same parts guy said, hold on I have to check something because a lot of these water pumps have a modified fitting we should install. Then the next time he knew nothing about that. Heath may have them made custom, BK95td made one by tapping the inside of it and just putting in adapter plug or drilled out a plug.

I theorize GM did that with the dual thermostat to maintian warmer temperatures, for emissions and efficiency. Although, then we beef up the cooling systems so they dont really get and stay that warm in normal operation.
 
There has to be some merit to the restrictor. Look at a 6.2 cooling system with the horizontal t-stat setup. No bypass blocker on the stat, however the diameter of the bypass is much smaller. The 6.5 it looks to be a 1 inch diameter bypass hose. My k-5s bypass is nothing more than a piece of 5/8" heater hose.

Smaller hose = more restriction, not to mention the opening for the coolant to flow through is less than 5/8", probably closer to 3/8" if not 1/4".
 
Well, I got the fitting from the old 95 WP which looks the same so I could experiment on it. Maybe I'll do that tomorrow. Too friggin hot to do anything else today but here's the skinny on intial test drive.
OK to recap...
Todays project boys and girls was upgrading my 93 with recycled parts.
As you know I was not happy with the performance of the 600$ recored Brass/copper rad from Production year 93. Well, my 93 had a 1 1/4 inch cheeseball rad in it and since I don't town anyway and I now have this 600$ rad I put it in the 93 which was what it came with from GM. I used the old WP off my 2000 for reasons stated in another thread .
Used a Hayden SD 2840 Spin on Clutch with the factory 9 blade fan from the 98 Burb.New GM Thermostat with single housing Got some interesting results.
At idle with the a/c on max with 102f/112HI temps outside it was idling at about 210 deg.Never seen one of these that hot at idle but the temps today are unprecedented for our region as it's humid as well.
Take off to Advance to PU some antifreeze. Hayden kicks in and let me tell you that 9 blade sounds way louder than the dmax fan. I still say it works better. The temps came down immediately and fast while driving. You knew that bitch was kicked in. Yesterday my burb with JK clutch was engaged but that Dmax fan was no where near as loud as the 9 blade steel. This was also my observations from past owned 6.5's. I still say the Dmax fan is snake oil. I know I'm a dangerous forum reader but I have tried pretty much every combination and these are my honest results. The temps dropped like a new brides panties as soon as I took off with some rpms. So...maybe the Copper brass rad is not a dud after all. It may not be any better but I don't think it is any worse either. I think my issues with it violently overheating in the burb the other day was the botch fan clutch mod I did. I will never do it again. Might as well of just hit the thing with a hammer and it would have been just as useless. Now of course this is apples to oranges as the 98 Burb and the 93 K3500 have basically nothing in common save for the 6.5TD
I am sure not having the tranny in the rad with the 93(nv4500) helps but man that temp dropped and it dropped fast but why so hot at idle ?
Does this mean the alum rad sheds heat better with lower airflow but the copper one sheds it faster with more airflow ?? I can tell you the 93 needed almost 2 gallons more coolant with the new rad.
 
BTW, today is the hottest day I have ever experienced in the 42 yrs I have been alive. I should be out in the Hamptons or on Fire Island getting drunk with a bunch of loose women instead of working on this junk....:rof:
 
Glad it all pretty well worked out for you. Does the 93 have the correct bypass blocking tstat in it?

The DMax fan probably would keep it cooler at idle. Why not do apples to apple comparison now and put the DMax fan on the 93 with hayden clutch, see which fan comes out ahead. Just because it doesnt make as much noise doesnt mean its not doing as much. Larger diameter smaller surface area fins with more aggressive pitch.
 
Yep and it had the right one in it. I replaced it anyway. For those who don't understand the whole bypass block off thing hopefully these pics worth 1000 words...:D

Maybe I'll try switching them when the weather breaks..Might as well have Velco on the upper shroud it's been off so many times lately.
 

Attachments

  • DSCF0013.jpg
    DSCF0013.jpg
    85.5 KB · Views: 11
  • DSCF0012.jpg
    DSCF0012.jpg
    85.2 KB · Views: 9
That is the 190* dual spring stat I believe. It has that extra cup area, it may or maybe not flow as much as the 195 or 180 which dont have that cup area. The 195 delco is just damn hard to find.
 
Dunno, got it from the Chevy dealer. What I can tell you is before I did all this to the 93 it ran consistent 210 no matter what. I don't trust the gauges though in this truck . They are screwey. The Alt gauge is way off, I know that for sure. Could hit it with the laser and see or throw a thermometer in the rad as this style has the cap right on the rad.

I do want to clarify one thing though....My deifinition of overheating is ANYTHING over 210 so when I say I'm overheating that just means it's higher than I'd like, but not boiling over or 240+ although I did hit that with the Copper rad, modded FC in the burb.
 
Acesneights1 said:
Supposedly GM makes it but I don't know the part # but do you have a pic of yours ?
Click to expand...

No I don't have a pic. From the outside it looks just like any other barb. But on the inside it is a solid piece of steel with a small hole bored through it. You're capable enough with fabbing things that you shouldn't have any problems doing like Barry did when he made his own.

Wow, this thread is getting a lot of action today and a lot of good info coming across. I'm really liking this and learning from this. Thanks to all who are contributing.

Don
 
I still can't believe you think the 20" steel is a better choice than the 21" Composite/Plastic D-Max Blade......Maybe you got the replacement White 6 bolt plastic blade....I'm baffled...:???:
 
brooklyn, I think he has mentioned elsewhere on the forum that he dispises plastic fans, and has had one or two grenade on him. had a buddy just have a fan grenade on him, so he is back to steel. so I think Kenny wants to trust the d-max fan, but has been kicked in the ass by a few in the past, so he will never trust a plastic fan.

I only go with 9 blade steel 20 inch cause it is cheap, and I can get by, as I dont have transmission heat in the cooling stack! go 5 speed! :D

my OCD is happy. the 93 got a 1993 brass radiator, so the truck is factory correct. ahhhhhhh. :)
 
You must log in or register to reply here.
Back
Top